Training Suggestion for QA Technical Writing

I guess I should post this in "Testers and Testing" but things look pretty dead there.

I need a good book recommendation or training for someone whose job it is to write manual test cases in professional technical english.
The person is without formal training for this, and worse, do not have english as first language (not that I'm to speak)

At the moment her writing (from technical point of view) are inconsistent and hard to follow, so I just want to get a good book to study in her free time.

Anyone?